Final answer:
The Office of the Comptroller of the Currency (OCC) regulates financial markets by supervising national banks and savings and loan institutions, while the NCUA and FDIC provide supervision and insurance for credit unions and bank deposits, respectively.
Step-by-step explanation:
Among the agencies mentioned, the Office of the Comptroller of the Currency (OCC) is responsible for regulating financial markets, specifically by overseeing the largest national banks and certain savings and loan institutions within the United States Treasury. The OCC is distinct from the National Credit Union Administration (NCUA), which supervises credit unions, and the Federal Deposit Insurance Corporation (FDIC), which insures bank deposits and supervises banking institutions to ensure financial stability and consumer protection. These agencies ensure a stable and secure financial system by monitoring banking activities, balance sheets, and adherence to various regulatory requirements.